As a process for producing an .alpha.-amino acid, there has been known a process which comprises treating an aldehyde or a ketone with an alkali cyanide and ammonium chloride (or ammonia) to produce the corresponding .alpha.-aminonitrile (Strecker synthesis), and hydrolyzing the obtained .alpha.-aminonitrile by concentrated hydrochloric acid or the like.
Moreover, there have been known another processes for producing .alpha.-amino acids, such as a process which comprises aminating an .alpha.-halo acid, an acylaminomalonic acid ester process, a process which comprises reducing and aminating an .alpha.-keto acid, and azlactone synthesis (a process which comprises reducing a substituted unsaturated azlactone, obtainable by reacting an aldehyde and an N-acylglycine with sodium acetate in acetic anhydride, by red phosphorus and hydrogen iodide in glacial acetic acid).
These processes, however, are not necessarily satisfactory in view of yield and applicability.